SAN File System

Synonyms

Shared-disk file system

Definition

The term SAN file system refers to a file system which transfers file data directly to/from a storage device through a SAN. A SAN file system often has the capability of coherency control such that multiple servers may share the file system volume and simultaneously access files stored in the volume. The term shared disk file system is also used to refer to a SAN file system.

Key Points

In contrast to local file systems, SAN file systems allow multiple servers to share file system volumes directly and to access the same file simultaneously. To achieve this, the SAN file system has the capability of coherency control between servers. File system software running on each server may cache file data in a main memory buffer. Suppose that two servers, A and B, have cached the same file X. If A and B were to update X independently at the same time, two versions of X might be generated. The SAN file system needs to let each server be aware of the...